Wrong or just human Nature?

What did I go and get myself into? When people you love and care about just get up and leave you alone, you do things you regret completely everything you do. Its only when you get to see them again that you see your wrong doing and change it as best as you can. I been called a lot and peoples words hurt and I don't think that they see your hurt. I think that why we have so much hate is because people do it to make themselves feel better. I never really understand why we do it... I guess its what makes us human. We hurt and kill for fun or to show our strength instead of how weak we really are.
Is this what life is always gonna be like? I mean we had a school shooting that was stopped because of what people here in my town has done to him and put him through. Why are we this way? If anyone had the answer I am sure life would be easier then this. We have it all based on race, gender, what someone believes are, and what they think is the right way. Everyone wants to be right and never wrong and when someone tells you are wrong you get angry at them and hate them.
You stay alone in life and you get in tight spots and do things you regret and that can hurt you. When my parents got a divorce, my boyfriend moved, and after I watched my very dear friend die.... I started to smoke and drink. I admit to sleeping around with a few guys because I lost that since of love that was in my life and I felt like I had to fill that hole in my heart. What I ended up doing was flushing my dreams down the toilet and had a lot of that on my back and I still do. I get dirty looks walking down the hall and in classes everyday. It made me feel like a piece of trash.
I can't take any of it back. I can't hit the rewind button and redo it. It is stuck with me forever. Truth is everyone makes a wrong choice here and there, sometimes its a big or its small. I lost my parents trust and ended up being sexually assaulted because of my choices. If I had a chance to redo it all I would and change it all but fact is I can't.